This is a proposal to develop a national Alzheimer's Disease Patient Registry (ADPR) using cases from Alzheimer Centers established by the National Institute of Aging. The specific aims of the ADPR during the three year award period are as follows: 1) to collect baseline data and uniform follow-up data on several thousand patients from the centers; 2) to validate empirically the consistency of disease markers, particularly, the accuracy of diagnosis by comparison of centers; 3) to refine criteria for diagnosis and prognosis by intensive review of registry data in preparation for future studies of national patterns of incidence and prevalence by age, sex, education, and other demographic factors; 4) to construct profiles and delineate courses of disease that apply to patients throughout the country and thereby set the stage for conducting efficient clinical trials; 5) to coordinate the comparison of instruments measuring multiple dimensions of patient status and the relative efficiency of abbreviated test batteries from which would evolve simple, economic, and readily applied criteria for mass use; 6) contingent on finding measures of progression of illness, to compare strategies of patient care used by various centers; 7) to train workers to use the technology of managing large databases; and 8) to provide epidemiologic and analytic support to centers that specialize in the study of autopsied and biopsied cases, new imaging technologies, neurochemical and immunological probes, environmental risk factors, and genetic factors. The proposed Registry is a Phase I or evolutionary ADPR. Building on a process of consensus between centers, the ADPR will use iterative analyses to refine diagnostic criteria, to test the adequacy of patient data for future studies, and to statistically validate associations found by individual centers. Achievement of these goals will make possible an effective national population-based registry capable of monitoring national incidence rates, establishing empirically validated diagnostic criteria suitable for prospective therapeutic trials, and designing research on the oragnization, structure of services, preventive measures, and control of medical costs.